Computational Complexity and other fun stuff in math and computer science from Lance Fortnow and Bill Gasarch

Tuesday, May 03, 2005

Dilemmas of Prisoners and Professors

Some interesting game theory and philosophy from the last couple of NUMB3RS
episodes. Usual spoiler warnings.

In the April 22nd episode Dirty Bomb there were three
suspects who wouldn't talk. Charlie, the mathematician, likened the
situation to Prisoner's
Dilemma and suggested putting the suspects in the same room, which
is usually the wrong thing to do in prisoner's dilemma. What Charlie
did was compute the utility for each suspect cooperating (with each
other and not the FBI) based on family considerations and their
previous record and convinced the one with the most to lose by
cooperating to defect and talk to the FBI. Clever, but I really wonder
if that would work in real life.

Last Friday's episode Sacrifice took a more philosophical
direction. A murdered think-tank computer scientist was developing a
program that measured academic potential based on where someone grew
up, down to a city block. If such a program actually worked, how
should a program be used, if at all? How far should one go to stop the
project?

Charlie and his physicist friend Larry ruminated on whether scientists
are responsible for how their research gets used, as well as a
discussion on the lonely life of a scientist at a lightly attended
memorial service for the murder victim. The episode also had a physics
joke I don't quite get.

Applied physicists are from Venus; Theoretical physicists wonder why
it spins in the other direction.

I really enjoy those discussions between Charlie
and Larry because they ask some interesting questions and add some
dimension to a public view of mathematicians and scientists.

Yeah, Venus' slow rotation sucks from a terraforming point of view - even if you could get rid of the oppressive atmosphere, it would take a huge amount of energy to spin it up to a reasonable day (a large fraction of the total gravitational potential energy). Around a billion large comets falling in from the Oort cloud would be needed. Better just to use all of the Sun's radiant energy over the course of a year in order to disassemble it and build a Niven ring :-).

Venus rotates clockwise as does Uranus and Pluto. So the quote refers to the different types of physists. Applied physicists accept that it spins clockwise, theoretical physicists try to understand how it could spin that way.